Chapter 8 Cellular Energy

Cooperative Activity What do you know about energy?

Energy - what we know Cannot be created or destroyed Can change forms Stored in chemical bonds

Energy - what we know (cont.) Released when bonds are broken Needed to form bonds

Review: Chemical Reactions Chemically changing substances Metabolism: sum of all the chemical reactions that occur in our body

Review: Chemical Reactions (cont.) Chemical equations show how substances change Reactants  Products Na + Cl  NaCl

Photosynthesis

Photosynthesis How plants convert solar energy into glucose Takes place in chloroplasts

Why is it called photosynthesis? Photo means “light” Synthesis means “to put together” What are we putting together? glucose

Chloroplasts Capture light Contain pigments like chlorophyll

Chloroplasts & Chlorophyll

Accessory Pigments Chlorophyll = main pigment Each pigment reflects a different color

Accessory Pigments (cont.) Carotene – Orange Xanthophyll – Yellow Anthocyanin – Red

Phases of Photosynthesis Sunlight is converted into ATP (aka light reaction) ATP is converted into glucose (aka dark reaction)

Photosynthesis: Chemical Equation Reactants 6 CO2 + 6 H2O -------------> C6H12O6 + 6 O2 Products Light http://www.biology.ualberta.ca/facilities/multimedia/uploads/alberta/Photo.html

What affects the rate of photosynthesis? Light Intensity Temperature Water Other

Why do leaves fall off the tree? Chlorophyll breaks down in cold temps No use for leaves so they fall off to save energy Trees hibernate in winter

What’s up with that tree? Why are Japanese Maple trees red? Do they perform photosynthesis?

ATP (Adenosine Tri-Phosphate) Portable form of energy “Energy currency” Delivers energy where needed in cell

Cellular Respiration Process of releasing energy stored in the bonds of glucose http://glencoe.mcgraw-hill.com/sites/dl/free/0078617340/164155/00053412.html

Step 1 – Glycolysis Takes place in cytoplasm Does not require oxygen (Anaerobic) 2 ATP produced

2. Fermentation (Aerobic) 2 ATP produced Occurs during rapid & heavy exercise Feel burning sensation in muscles

2. Respiration Takes place in mitochondria Requires oxygen (aerobic) 34 ATP produced

and the total is… 4 ATP: Glycolysis & Fermentation 36 ATP: Glycolysis & Respiration

~ Cellular Respiration ~ The Chemical Equation Reactants C6H12O6 + 6 O2  6 CO2 + 6 H2O + ATP Products

Comparing the reactions Photosynthesis 6 CO2 + 6 H2O + Light  C6H12O6 + 6 O2 Cellular Respiration C6H12O6 + 6 O2  6 CO2 + 6 H2O + ATP